*/
  @CanIgnoreReturnValue
  @Override
  public int setCount(E element, int count) {
    checkNotNull(element);
    checkNonnegative(count, "count");
    while (true) {
      AtomicInteger existingCounter = safeGet(countMap, element);
      if (existingCounter == null) {
        if (count == 0) {
          return 0;
        } else {

@app.get("/items/valid", response_model=Item)
def get_valid():
    return Item(aliased_name="valid", price=1.0)


@app.get("/items/coerce", response_model=Item)
def get_coerce():
    return Item(aliased_name="coerce", price="1.0")


@app.get("/items/validlist", response_model=list[Item])
def get_validlist():
    return [
        Item(aliased_name="foo"),

    owner_ids: Optional[list[int]] = None


@app.get("/items/valid", response_model=Item)
def get_valid():
    return {"name": "valid", "price": 1.0}


@app.get("/items/coerce", response_model=Item)
def get_coerce():
    return {"name": "coerce", "price": "1.0"}


@app.get("/items/validlist", response_model=list[Item])
def get_validlist():
    return [
        {"name": "foo"},
        {"name": "bar", "price": 1.0},

@app.get("/items/object", response_model=Item)
def get_object():
    return Item(
        name="object", date=datetime(2021, 7, 26), price=1.0, owner_ids=[1, 2, 3]
    )


@app.get("/items/coerce", response_model=Item)
def get_coerce():
    return {"name": "coerce", "date": datetime(2021, 7, 26).isoformat(), "price": "1.0"}


@app.get("/items/validlist", response_model=list[Item])
def get_validlist():
    return [

Todo lo que necesitamos hacer es manejar el request dentro de un bloque `try`/`except`:

{* ../../docs_src/custom_request_and_route/tutorial002_an_py310.py hl[14,16] *}

Si ocurre una excepción, la `Request instance` aún estará en el alcance, así que podemos leer y hacer uso del request body cuando manejamos el error:

{* ../../docs_src/custom_request_and_route/tutorial002_an_py310.py hl[17:19] *}

Nils-Hero Lindemann <******@****.***> 1765374874 +0100

If there's no `gzip` in the header, it will not try to decompress the body.

That way, the same route class can handle gzip compressed or uncompressed requests.

{* ../../docs_src/custom_request_and_route/tutorial001_an_py310.py hl[9:16] *}

### Create a custom `GzipRoute` class { #create-a-custom-gziproute-class }

```
http://127.0.0.1:8000/items/foo-item?needy=sooooneedy
```

...this would work:

```JSON
{
    "item_id": "foo-item",
    "needy": "sooooneedy"
}
```

And of course, you can define some parameters as required, some as having a default value, and some entirely optional:

{* ../../docs_src/query_params/tutorial006_py310.py hl[8] *}

In this case, there are 3 query parameters:

So, even with the code above that doesn't use Pydantic explicitly, FastAPI is using Pydantic to convert those standard dataclasses to Pydantic's own flavor of dataclasses.

And of course, it supports the same:

* data validation
* data serialization
* data documentation, etc.

This works the same way as with Pydantic models. And it is actually achieved in the same way underneath, using Pydantic.

Sebastián Ramírez <******@****.***> 1765917160 -0800